sox-stream

A stream wrapper around SoX. Transcode audio streams easily!

Why

The other implementations I found felt klunky to use. This module implements a streaming interface. (If you don't know how to use streams, I recommend reading the stream handbook.)

Examples

Simple transcode:

var sox = require('sox-stream')
var fs  = require('fs')

fs.createReadStream('song.wav')
	.pipe( sox({ output: { type: 'flac' } }) )
	.pipe( fs.createWriteStream('song.flac') )

Lower volume:

var sox = require('sox-stream')
var fs  = require('fs')

var src = fs.createReadStream('song.flac')
var lowerVolume = sox({ input: { volume: 0.8 }, output: { type: flac }})
var dest = fs.createWriteStream('song2.flac')

src.pipe(lowerVolume).pipe(dest)

Transcode with options and error handling:

var sox = require('sox-stream')
var fs  = require('fs')

var src = fs.createReadStream('song.ogg')
var transcode = sox({
	output: {
		bits: 16,
		rate: 44100,
		channels: 2,
		type: 'wav'
	}
})
var dest = fs.createWriteStream('song.wav')
src.pipe(transcode).pipe(dest)

transcode.on('error', function (err) {
	console.log('oh no! ' + err.message)
})

API

var sox = require('sox-stream')

var transform = sox(options)

• options object required - The following parameters are supported:
  • soxPath string optional - The path to SoX. E.g. 'C:\Program Files\Sox\sox.exe'. Defaults to 'sox', which works if the SoX binary is in your path.
  • global object optional - Global SoX options
  • input object optional - These options will be used to interpret the incoming stream.
  • output object required - These options will be used to format the outgoing stream. When an output option isn't supplied, the output file will have the same format as the input file where possible. (Except type, which you must always pass in.)
  • effects string|array of strings/numbers optional
• Returns transform, a stream to pipe data through. The stream emits 'error' events when there is an error.

options object

An object of options. Every option is optional except options.output.type is required.

If you want an exhaustive list of each SoX option in depth, take a look at the SoX documentation.

Internally, these options are transformed into the command-line arguments passed to a SoX child process.

options.global object|array of strings/numbers

You can supply an array of strings/numbers, or an object that will be transformed into an array of strings/numbers using hash-to-array.

Currently, sox-stream only supports one input file, so some of these options don't really make sense.

var transform = sox({
	global: {
		buffer: 4096,
		norm: true,
		'single-threaded': true
	},
	output: { type: 'ogg' }
})

options.input / options.output object|array of strings/numbers

You can supply an array of strings/numbers, or an object that will be transformed into an array of strings/numbers using hash-to-array.

var transform = sox({
	input: [
		[ '--volume', 1.1 ],
		[ '--endian', 'big' ],
		[ '--no-glob' ]
	],
	output: { type: 'ogg' }
})
// same as
var transform = sox({
	input: {
		volume: 1.1,
		endian: 'big',
		'no-glob': true
	],
	output: [
		'--type', 'ogg'
	]
})
// same as
var transform = sox({
	input: '--volume 1.1 --endian big --no-glob',
	output: '--type ogg'
})

options.effects string|array of strings/numbers/arrays

Please see the SoX Documentation on Effects to see all the options.

Pass them into sox-stream like this:

var transform = sox({
	input: { type: 'ogg' },
	output: { type: 'wav' },


	effects: 'speed 1.5 swap'
	// same as
	effects: [
		'speed 1.5 swap'
	]
	// same as
	effects: [
		'speed', 1.5,
		'swap'
	]
	// same as
	effects: [
		[ 'speed', '1.5' ],
		'swap'
	]
})

Install

• Install SoX. You can download it, or you can do apt-get install sox
• Install this package with npm: npm install sox-stream

Test

To run the tests, you must have SoX in your PATH. Then run: npm test

I run the tests using SoX 14.4.2, but other versions of SoX should work as well.

Codec Support

FLAC

• Problem: FLAC was disabled accidentally in 14.4.1 (SourceForge default). [Stack Overflow]
• Solution: Install SoX 14.4.2.

MP3

• Problem: MP3 is proprietary.
• Solution: Compile the LAME encoder, and/or the MAD decoder.
• Links:
  • Windows (Precompiled)
  • Windows (How-To)
  • Ubuntu (How-To)
  • Ubuntu (How-To) 2
  • CentOS (How-To)

License

MIT